Effect of a pre-deposited ni layer on the hydrogen evolution performance of an electroplated ni-p/cfp composite catalyst in acidic media

In this work, we studied the effect of a pre-deposited Ni layer on the hydrogen evolution performance of Ni-P composite catalysts in acidic media. To elucidate the effect of the pre-deposited Ni layer, pristine Ni-P/carbon fiber paper (CFP) and Ni-P/Ni/CFP composite catalysts were prepared. As a result, the Ni-P/Ni/CFP with a pre-deposited Ni layer had a 21.7% lower overpotential (141 mV) at -10 mA cm-2 than a Ni-P/CFP composite catalyst (180 mV) in 0.5 M H2SO4 solution. This was because the electrochemical surface area and P ratio at the surface of Ni-P/Ni/CFP (2.38 m2 g-1 and 30.26 at%) are 13.2% and 5.4 at% higher than those of the pristine Ni-P/CFP catalyst (1.79 m2 g-1 and 24.87 at%), respectively. Furthermore, the more porous morphology of Ni-P/Ni/CFP could facilitate the effective removal of the produced hydrogen bubbles, leading to the minimized fluctuation of the hydrogen production rate by providing a sufficient surface area for the detachment of small hydrogen bubbles.